Compacting devices which operate according to the so-called damper principle are used particularly in the field of compacting soil. An even plate or a roller body (drum), which forms the soil contact surface, is excited to oscillations by means of an unbalance exciter. The plate or the roller body is connected via a spring damper system to a damper mass arranged above it, which is also excited to oscillations via the spring damper system. If the damper mass oscillates with the same phase with the same frequency (1:1 resonance) or with half of the frequency (2:1 resonance) of the plate or the roller body, a maximum soil compacting force is attained by this machine concept (damper principle), which corresponds to the power of substantially larger or heavier machines without damper mass.
Due to the system, the problem arises in case of such soil compacting devices that the oscillating behaviour of the plate or the roller body, which excites the damper mass to oscillations, is influenced by the stiffness of the soil to be compacted, which may be different in different locations and which additionally changes during the compacting of the soil. In practice this leads to the fact that simpler devices with fixed exciter frequencies can rarely be operated at their optimal operating point (1:1 resonance or 2:1 resonance) and therefore cannot exploit their entire potential. Furthermore it is possible to experience an earlier wear or even destruction when operating them in a suboptimal range.
In case of technically more complex systems with damper exciters which can be regulated the desired resonance state can be reached by varying the exciter frequency in large parts, such that at least the last mentioned problem can be avoided. However, in this case there is the disadvantage that the required exciter frequency for producing the resonance state is often energetically suboptimal, which again leads to the fact that these devices do not entirely exploit their power potential as well.
Therefore, the invention has the objective to provide technical means by means of which the disadvantages of the prior art mentioned above can be at least partially overcome.
This objective is solved by present invention.
Accordingly, a first aspect of the invention relates to an arrangement for providing a pulsing compressive force. The arrangement comprises an exciter part with an unbalance exciter for producing an intermittent exciter force and with a contact surface for transmitting a force component of the exciter force, directed perpendicularly to the contact surface, as a pulsing compressive force, to a tool or a work surface to be impinged with the compressive force. Furthermore, the arrangement comprises a vibration damper part which is connected to the exciter part by means of a spring-damper unit, for forming a system capable of oscillating and which is excited to resonant oscillations by the unbalance exciter.